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Page::reset_for: stop zeroing pages #2804

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Merged
cloutiertyler merged 1 commit into from
May 28, 2025
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Page::reset_for: stop zeroing pages #2804

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12 changes: 10 additions & 2 deletions crates/table/src/page.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1837,8 +1837,16 @@ impl Page {
/// The reset page supports `max_rows_in_page` at most.
pub fn reset_for(&mut self, max_rows_in_page: usize) {
self.header.reset_for(max_rows_in_page);
// SAFETY: We just reset the page header.
unsafe { self.zero_data() };

// NOTE(centril): We previously zeroed pages when resetting.
// This had an adverse performance impact.
// The reason why we previously zeroed was for security under a multi-tenant setup
// when exposing a module ABI that allows modules to memcpy whole pages over.
// However, we have no such ABI for the time being, so we can soundly avoid zeroing.
// If we ever decide to add such an ABI, we must start zeroing again.
//
// // SAFETY: We just reset the page header.
// unsafe { self.zero_data() };

@cloutiertyler cloutiertyler May 28, 2025

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We do not need to zero pages as long as the pages aren't shared between modules. If the page pool is specific to a single tenant, we're okay.

@Centril Centril May 28, 2025

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That's true, but in our current setup, we do share pages between modules.

@gefjon gefjon May 28, 2025

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The page pool is very much global right now. We don't currently expose pages' raw bytes to customers, as we don't expose a way to download snapshots nor have a raw page ABI for modules. We would like to do both of those things in the future, though, and so we'll need to either revert this change, or make it configurable. I'll make a ticket.

}

/// Sets the header and the row data.
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